1. Field of the Invention
The present invention relates to an uncotrolled angular displacement compensating device for compensating an uncontrolled angular displacement of a robot hand mounted on an industrial robot of the linkage system in which the robot hand is shifted by means of a linkage and the robot hand is turned through an angle of 90 degrees or 180 degrees by the operating force of an actuator transmitted thereto through bevel gears mounted on a joining unit interconnecting the robot hand mounting link of the linkage and the robot hand, respectively.
2. Description of the Prior Art
In an industrial robot of such a system, the hand mounting link mounted with a robot hand turns relative to the robot hand when the robot hand shifting linkage is expanded or contracted, and hence one of a set of bevel gears mounted on the joining unit turns relative to the other. Consequently, the uncontrolled angular displacement of the robot hand from a correct position occurs, which makes the smooth attachment of a work to and removal of a work from the robot hand, and in the worst case, makes the attachment of a work to and the removal of a work from the robot hand impossible.